Photoflash device

ABSTRACT

A photoflash device with a photoflash lamp mounted within a reflector, the lamp being mountable in the reflector only in one or the other of two 180* apart axially oriented positions, has only one moisture indicator spot so located on the inside wall of its transparent envelope as to be viewable from in front of the reflector either directly or by reflection off the reflector irrespective of which one of the axially oriented positions the lamp is mounted in within the reflector.

United States Patent 1191 Anderson June 12, 1973 PHOTOFLASH DEVICEInventor: Robert M. Anderson, Pepper Pike, Ohio Assignee: GeneralElectric Company,

Schenectady, N.Y.

Filed: Dec. 30, 1971 [21] Appl. No.: 214,246

[52] US. Cl. 240/1.3

[51] Int. Cl. G03b 15/02 [58] Field of Search 240/13; 95/11;

[56] References Cited UNITED STATES PATENTS 3,609,331 9/1971 Fink et a1240/13 2,726,527 12 1955 Pipkin 431/95 2,993,008 7/1961 Anderson 431/95X 3,597,602 8/1971 Divoky et al. 240/13 Primary ExaminerSamuel S.Matthews Assistant ExaminerFred L. Braun Atlorney.lames J. Lazna, FrankL. Neuhauser,

Oscar B. Waddell et a1.

57 ABSTRACT A photoflash device with a photoflash lamp mounted within areflector, the lamp being mountable in the reflector only in one or theother of two 180 apart axially oriented positions, has only one moistureindicator spot so located on the inside wall of its transparent envelope.as to be viewable from in front of the reflector either directly or byreflection off the reflector irrespective of which one of the axiallyoriented positions the lamp is mounted in within the reflector.

4 Claims, 4 Drawing Figures PHOTOFLASH DEVICE BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates in general tophotoflash devices comprising a photoflash lamp mounted within areflector, and more particularly to such a device having a singlemoisture indicator spot on the inside wall of the lamp envelope.

2. Description of the Prior Art Certain types of flash lamps in use atpresent, particularly those of miniature size such as that commonlyreferred to as AG-l type flash lamps, are for the most part fixedlyassembled in place within a cooperating miniature size reflector to forma combination lampreflector unit or assembly. Several of theselampreflector assemblies are commonly mounted adjacent one another toform a multiple flash lamp array of which the conventional flashcube isone well-known embodiment. Linear arrays of such flash lamp-reflectorassemblies are also well-known in the art.

To provide the flash lamp manufacturer as well as user with a readilyvisible indication as to the operative condition of the lamp, i.e.,whether or not any atmospheric air has leaked into the lamp such aswould adversely affect its flashability, it has been customary practiceto provide an indicator spot of a so-called chemical leak detectormaterial on the inside wall of the lamp envelope which undergoes achange in color in the event contaminating atmospheric air along withthe water vapor normally contained therein should penetrate into theinterior of the envelope. The complex salt cobaltous-cobaltic cyanide isparticularly effective for such purpose. In the anhydrous state, such asalt is blue; in the hydrated state, the salt is pink. However, becauseeach of the flash lamps in the aforementioned flashcube array, as wellas in most other multiple flash lamp arrays, are generally mounted inone or the other of two predetermined axially oriented positions 180apart within the associated reflector, it has been customary heretoforeto employ two such indicator spots located diametrically opposite oneanother on the envelope wall and spaced therearound approximately 90from the axial mounting plane of the lamp so that no matter which of thetwo 180 apart oriented positions the lamp is mounted in within thereflector, one or the other of the indicator spots of the lamp envelopewill always face outwardly of the reflector so as to be exposed to theview of one examining the lamp. It was reasoned that the provision oftwo such diametrically opposed indicator spots on the lamp envelopewould thus eliminate the need for orienting and mounting the lamp inonly one predetermined axially oriented position within the reflector anoperation that would be time-consuming and very difflcult to perform onthe automatic high operating speed production equipment conventionallyemployed to manufacture such flashcube assemblies. But the provision oftwo indicator spots on each lamp envelope instead of one obviouslyentails the drawback of doubling the amount and thus the cost of theindicating material employed in the manufacture of the lamps and alsointroducing an extra indicator spot application step into the overalllamp manufacturing procedure.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a flash lamp and reflector assembly having only one moistureindicator spot on the inside wall of the flash lamp envelope which isvisible from the front of the reflector either directly or by reflectionoff the reflector irrespective of which one of two apart axiallyoriented mounting positions of the lamp it is mounted in within thereflector.

Another object of the invention is to provide a multiple flash lamparray comprised of a plurality of adjacent flash lamp and reflectorassemblies the individual flash lamps of which are each provided withonly one moisture indicator spot which is visible from the front of therespective reflector either directly or by reflection off the reflectorirrespective of which one of two 180 apart axially oriented mountingpositions of the lamp it is mounted in within the respective reflector.

Briefly stated, in accordance with one aspect of the invention, theflash lamp of a combination flash lamp and reflector assembly of thetype wherein the flash lamp is mountable in either one of two 180 apartaxially oriented positions within the reflector, is provided with onlyone moisture indicator spot on the inside wall of the flash lampenvelope, the indicator spot being located within either one of twodiametrically opposite arcuate extents of the lamp envelope, eachcentered relative to the axial plane of the lamp envelope extendingtransversely to the reflector axis whereby the indicator spot is visiblefrom in front of the reflector either directly or by reflection off thereflector irrespective of which one of the two 180 apart axiallyoriented positions the flash lamp is mounted in within the reflector.

Further objects and advantages of the invention will appear from thefollowing detailed description of a species thereof and from theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. 1 is an elevation on an enlarged scale of a photoflash device inthe form of a flashcube embodying the invention, with the moistureindicator spot of the flash lamp being shown as directly visible.

FIG. 2 is a view similar to FIG. 1 but showing the flash lamp mountedinstead in the flashcube reflector in a position rotated 180 from thatof FIG. 1 and showing the moisture indicator spot visible as a reflectedimage off the reflector instead of directly as in FIG. 1.

FIG. 3 is an elevation on an enlarged scale of the flash lamp of thephotoflash device comprising the invention, and

FIG. 4 is a sectional view on the line 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, theinvention is there illustrated as embodied in a conventional flashcubecomprising an array of four photoflash devices or combination flashlamp-reflector assemblies 1 each embodying the invention and mountedadjacent one another, with adjacent ones of the devices I mounted atright angles to each other and with their reflectors 2 facing outwardlyto form four sides of a cube. Each flash lampreflector unit or assembly1 is comprised of a miniature size flash lamp 3, such as that commonlyreferred to as an AG-l type flash lamp, mounted within the innermostpart of the associated reflector 2 which, as is customary, is ofgenerally parabolic curvature. As shown in FIG. 3, the flash lamp 3 iscomprised of a tubular shaped light-transmitting hermetically sealedglass envelope 4 which is formed at one end with an external flattenedpress seal portion 5. Sealed into the envelope 4 is a lamp mountstructure 6 comprised of a pair of lead-in wires 7, 8 which are fixedlysupported in spaced side-by-side relation by a glass bead 9 fusedtherearound. The lead-in wires 7, 8 are sealed through the flattenedpress seal and extend outwardly in an endwise direction therefrom. Anignition filament 10 of tungsten or a tungsten-rhenium alloy is mountedwithin the envelope 4, the filament being connected across the innerends of the lead-in wires 7, 8. Coatings ll of a suitable primermaterial, such as an admixture of zirconium, magnesium and potassiumperchlorate powders bonded together by a binder such as nitrocellulose,are provided on the inner tip ends of the lead-in wires 7, 8 and on atleast the opposite end portions of the filament 10 where it connectswith the lead-in wires. The envelope 4 contains a loosely distributedquantity 12 of a suitable light-producing filamentary combustiblematerial such as, for example, a shredded foil of zirconium, aluminum orhafnium, together with a filling of a combustion-supporting gas such asoxygen at a suitable pressure up to as high as several atmospheres,e.g., 7 atmospheres or so. The envelope 4 is formed, at the end thereofopposite its press seal end 5, with an exhaust tip 13 left by thetipping off of a glass exhaust tubulation on the envelope after theevacuation and filling thereof through the exhaust tubulation with thecombustion-supporting gas filling.

While the invention is illustrated as applied to flash lamp-reflectorassemblies 1 employing flash lamps 3 of the so-called electricallyignited type having an ignition filament 10 which is adapted to beheated by the passage of an electric current therethrough from a batteryor other source of electric power, it should be understood that theinvention is applicable as well to flash lamp-reflector assemblies 1employing flash lamps having various other type of lamp ignition meanssuch as, for example, the percussively ignited type flash lamps whichare employed in conventional percussive-ignited flashcubes in common useat present under the commercial designation Magicube and which areignited by the striking of a hammer blow against a readily deformablemetal ignition tube which contains a percussively ignitable primer orfulminating material and is sealed into and opens into the interior ofthe lamp envelope. Such percussively ignited type flash lamps aredisclosed, for example, in U.S. Pat. No. 3,535,063, Anderson et al.

The reflectors 2 of each flash lamp'reflector assembly 1 may beconstituted of preformed plastic sheet material having alight-reflective coating and defining an inwardly dished individuallight reflecting surface 14 of suitable shape such as generallyparabolic curvature, as is conventional in customary flashcube and othermultiple photoflash lamp arrays. To enable the flash lamp 3 to bepositioned within the innermost region of the reflecting surface 14 ofthe reflector 2 and contained more or less entirely within the confinesthereof, the reflector 2 may be formed with a tunnel portion 15 at itsinnermost region for partially accommodating therein the tubular glassenvelope 4 of the flash lamp, as shown in FIG. 4. The tunnel portion 15extends all the way down to the bottom of the reflector 2 to form ashroud portion 16 at its lower end for accommodating therein the entirelower end portion of the flash lamp 3.

The photoflash device 1 may be provided with the customary base 17 madeof a suitable synthetic plastic for mounting the device on a camera. Inthe case of the particular flashcube array illustrated employing flashlamps 3 of the electrically ignited type, the base 17 includes aplatform support portion 18 of substantially square shape, with itsedges bowed outwardly a slight amount, on which platform theorthagonally arranged array of reflectors 2 rest. The platform support18 has a plurality of apertures through which the lead-in wires 7, 8 ofthe respective flash lamps in the array extend to the under side wherethey are bent around an annular contact ring or collar 19 integral withand depending from the under side of the platform support to form theelectrical contacts 7, 8 for the individual flash lamps of the array.The base 17 is also formed with a center post 20 depending from theunder side of the platform support 18 and terminating in a plurality ofradially outward extending retaining lugs 21 adapted to engage withlocking or clamping means in the flashcubereceiving socket of a camerato retain the flashcube in place in the socket. A transparent orlight-transmitting cover or shield 22 ofa single molded piece of asuitable synthetic plastic material such as polystyrene and ofsubstantially cubic shape is disposed over the array of flashlamp-reflector assemblies 1 to provide a protection from possiblyrupturing flash lamps in the array as well as to prevent direct touchingof the lamps while they are still in their highly heated conditionimmediately following the flashing thereof. The cover 22 is permanentlyaffixed at its bottom edge to the platform support 18 by suitable meansas, for example, by an adhesive or by heat-sealing or ultrasonicwelding.

In the illustrated flashcube array, and as is generally customary inmost other type multiple flash lamp arrays such as linear type arrays,the individual flash lamps 3 are mounted in their associated reflectors2 with the axis XX (FIG. 3) of the lamp envelope 4 disposed transverselyto the axis RR (FIG. 4) of the reflecting surface 14 of the associatedreflector 2, and with the lamp oriented about its axis to position theplane PP (FIG. 4) of its flattened press portion 5 transversely to thereflector axis RR. The mounting of each flash lamp 3 in such an axiallyoriented position in its associated reflector 2 serves to align theouter end portions of the lead-in wires 7, 8 protruding straight outfrom the press seal 5 of the lamp with the outer side wall of thecontact ring 19 on the flashcube base 17 so that these protruding wireportions, during the flashcube assembly operation, can be threadedstraight down through the apertures provided for them in the platformsupport 18 and will thus extend closely alongside the outer side wall ofthe contact ring 19 in position for bending therearound to form the lampcontacts 7, 8' thereon. It will be apparent, however, that there are twol apart axially oriented positions of the flash lamp 3 in which it canbe mounted in the reflector 2 with the plane of its flattened press sealportion 5 disposed in the above-specified manner extending transverselyto the axis RR of the associated reflector 2.

It has been common practice in the flash lamp art to provide a smallspot of a suitable chemical leak detector or moisture indicatormaterial, such as the complex salt cobaltous-cobaltic cyanide, on theinside wall of the flash lamp envelope near the press seal end 5 thereofto indicate to a lamp viewer, by change of color, the presence in theenvelope of water vapor that may have penetrated into the envelope fromthe ambient atmosphere and thus indicate to the user that the lamp is aso-called leaker and therefore will not flash properly. In the case ofthe flash lamp-reflector assemblies employed heretofore in flashcubearrays, two such moisture indicator spots have generally been providedon the inside wall of each flash lamp envelope, the two indicator spotsbeing located on more or less diametrically opposite sides of theenvelope and generally in that axial plane of the lamp extending normalto the plane PP of the lamp press portion 5 and parallel to thereflector axis. The use of two such diametrically opposed indicatorspots on the lamp thus eliminated the need for performing thetime-consuming and difficult manufacturing operation of orienting andmounting the lamp in only one predetermined axially oriented positionwithin the reflector since no matter which one of the two 180 apartaxially oriented positions the lamp was then mounted in within thereflector 2, one or the other of the two indicator spots would always befacing outwardly of the reflector and thus exposed to the direct view ofone viewing the flash lamp array.

In accordance with the invention, it has been found that by locating amoisture indicator spot 23 of the character described hereinabove withincertain predetermined arcuate extents of the flash lamp envelope 4, onlyone moisture indicator spot 23 need be provided on the envelope of theflash lamp 3 mounted in the reflector 2 while still being visible to theviewer, either directly or by reflection off the reflector 2,irrespective of which one of the two 180 apart predetermined axiallyoriented mounting positions of the flash lamp it happens to be mountedin within the reflector 2 during the manufacture of the assembly 1. Tothis end, the single indicator spot 23 on the envelope 4 of a flash lamp3 mounted in a reflector 2 is located within one or the other of thosediametrically opposite arcuate extents a (FIG. 4) of the lamp envelope4, centered on the lamp mounting plane PP positioned tranversely of thereflector axis R-R, which extent approximately 60 around the lamp axisXX, i.e., approximately 30 to either side of the lamp mounting plane PPas indicated at b." With such a located single indicator spot 23 on theflash lamp 3, the spot 23 will be visible to the viewer of the flashlamp-reflector assembly 1, either directly or by reflection off thereflector 2 from the front thereof, if the flash lamp 3 happens to bemounted, in the reflector 2 during the production manufacture of theassembly 1, in that axially oriented mounting position of the lamp inthe reflector which results in the single indicator spot 23 facingoutwardly of the reflector, as shown in FIG. 1 and in solid lines inFIG. 4. On the other hand, if the flash lamp 3 happens to be mounted inthe reflector 2, during the production manufacture of the assembly 1, inthat axially oriented mounting position of the lamp 3 which results inthe single indicator spot 23 facing inwardly of the reflector 2, asshown in dotted lines in FIGS. 2 and 4, then in that case the indicatorspot 23 will be visible to the viewer, from the front of the reflector,as a reflected image 23' off the reflector 2, as indicated in FIG. 2 andby the arrows 23" in FIG. 4. Thus, irrespective of which one of its two180 apart axially oriented mounting positions in its mounting plane PPthe flash lamp 3 happens to be mounted in within the reflector 2, thesingle indicator spot 23 located on the envelope 4 in the manneraccording to the invention nevertheless will be clearly visible to theviewer of the flash lamp-reflector assembly 1 either directly, as shownin FIG. 1, or indirectly as a reflected image 23' off the reflector 2,as shown in FIG. 2. If the single indicator spot 23 is located on theenvelope 4 a substantial distance beyond the prescribed approximately 30limit to one or the other side of the mounting plane PP of the flashlamp 3, then in that event the indicator spot 23 most likely would notbe visible by reflection off the reflector 2 in the case where the lamp3 is mounted in the reflector with its one indicator spot 23 facinginwardly thereof, the reflected image 23 of the indicator spot 23 insuch case either being obstructed or blocked off from view by theoutermost side portions of the flash lamp 3 itself, or else beingreflected off the generally cylindrically curved wall of the tunnelportion 15 of the reflector 2 in a direction radially back toward thecenter axis XX of the flash lamp 2 so as to also be effectively blockedoff from view by the lamp itself.

It will be apparent, therefore, that by making possible the employmentof only one moisture indicator spot 23 on the flash lamp envelope 4 of aflash lamp-reflector assembly 1 instead of the two diametricallyopposite indicator spots heretofore customarily employed in suchassemblies, while still being able to see the indicator spot or itsreflected image irrespective of which one of its two axially orientedpositions the lamp is mounted in within the reflector 2, the inventiontherefore has the advantage of requiring only half the amount ofmoisture indicator material, in the production manufacture of theassemblies 1, as that previously required and thus effects anapproximate 50 percent saving in material cost. Moreover, theseadvantages are realized without any need for incorporating into themanufacturing procedure for producing the flash lamp-reflectorassemblies 1 any special manufacturing operation for orienting the flashlamp 3 into only one predetermined axially oriented position formounting in the reflector 2 in order to assure that the one indicatorspot will always be located in a position facing outwardly of thereflector 2 so as to be exposed to view. Such a special lamp orientingoperation would be time-consuming and most difficult to perform. Also,assemblies 1 embodying the invention exhibit gains of around 3 percentin zonal lumen seconds light output.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a photoflash device comprising a base, a reflector positioned withrespect to said base, and a photoflash lamp mounted on said baseadjacent the innermost region of said reflector, said photoflash lampincluding an elongated light-transmitting envelope disposed with itslongitudinal axis extending transversely to the reflector axis ofsymmetry, said lamp being mountable on said base in either one of twopositions spaced apart about its longitudinal axis, said lamp beingmountable on said base, in each of said positions, with its longitudinalaxis in a mounting plane disposed approximately normal to the reflectoraxis, the combination therewith of a single spot of a moistureindicating material on the inside wall of said envelope, said indicatorspot being located with its center on a line passing through thelongitudinal axis of said envelope and extending at an angle ofapproximately 30 to either side of said mounting plane in each of saidtwo posi- 3. A photoflash device as specified in claim 1 wherein aplurality of said photoflash devices are mounted adjacent one another.

4. A photoflash device as specified in claim 1 including four of saiddevices located adjacent one another, with adjacent ones of said devicesmounted at right angles to each other and with their said reflectorsfacing outwardly to form four sides of a cube.

1. In a photoflash device comprising a base, a reflector positioned withrespect to said base, and a photoflash lamp mounted on said baseadjacent the innermost region of said reflector, said photoflash lampincluding an elongated lighttransmitting envelope disposed with itslongitudinal axis extending transversely to the reflector axis ofsymmetry, said lamp being mountable on said base in either one of twopositions spaced 180* apart about its longitudinal axis, said lamp beingmountable on said base, in each of said positions, with its longitudinalaxis in a mounting plane disposed approximately normal to the reflectoraxis, the combination therewith of a single spot of a moistureindicating material on the inside wall of said envelope, said indicatorspot being located with its center on a line passing through thelongitudinal axis of said envelope and extending at an angle ofapproximately 30* to either side of said mounting plane in each of saidtwo positions whereby the indicator spot is visible from in front of thereflector either directly or as a reflected image off the reflectorirrespective of which one of the said two positions the lamp is mountedin relative to the reflector.
 2. A photoflash device as set forth inclaim 1 wherein the said reflector is formed with a lamp-receivingtunnel at its innermost region within which the said envelope of thelamp is nested to a depth around 20 to 30 percent of its diameter.
 3. Aphotoflash device as specified in claim 1 wherein a plurality of saidphotoflash devices are mounted adjacent one another.
 4. A photoflashdevice as specified in claim 1 including four of said devices locatedadjacent one another, with adjacent ones of said devices mounted atright angles to each other and with their said reflectors facingoutwardly to form four sides of a cube.